Refrigerating apparatus



Juhe 12, 1934. J R HQRNADAY 1,962,771

REFRIGERATI NG APPARATUS Filed Aug 31, 1931 INVENTOR 15' ATTORNEIYJ- Patented June 12, 1934 PATENT o Frrcr:

REFRIGERATING APPARATUS James R. Hornaday, Dayton, Ohio, assignor to Frigidaire Corporation, Dayton, Ohio, a corporation of Delaware Application August 31,

8 Claims.

This invention relates to refrigerating apparatus and more particularly to intermittently operated motor-compressor units provided with an unloading means.

The objects of my invention include the provision of an improved unloading means for an intermittently operated motor-compressor unit of a refrigerating system and an improved check valve for the unloading means. I

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

5 In the drawing The figure is a view of a refrigerating system embodying fea'tures of the invention showing a portion of the system diagrammatically and showing an enlarged view in cross section of the motor compressor unit. I, v I I Motor compressor units are generally intermittently operated, and where they are motor driven, it is generally desirable to unload the compressor temporarily when starting in order to reduce 5 the load on the motor until a predetermined speed is reached. Sometimes an equalizing chamher is placedon the intake of the compressor,

and this chamber is provided with a check valve to prevent the flow of high pressure medium to the suction part of the apparatus. Where the check valve is not provided with aquick seating means, it is liable to seat improperly and allow a continuous flow of high pressure medium into the low pressure part of the apparatus to. which the compressor is connected. It is the purpose of this invention to provide a checl; valve which permits the flow of the medium to be compressed without undue resistance while the compressor is operating, and which quickly seats after the 40 compressor has stopped and prevents a gradual seepage of the high pressure medium into the low pressure part of the appartaus to which the compressor is connected.

It is customary to operate motor-compressor 4 units of refrigeration systems intermittently.

'With such a system the motor-compressor unit is stopped when the temperature and consequently the pressure in the evaporator is lower and if started when the temperature and consequently the pressure within the evaporator is high. Since the discharge side of the compressor is at condenser pressure and the suction side is normally under evaporator pressure, the compressor must obviously start out under a heavy load and consequently a motor having a high startssi, Serial No. 560,291 (01. 62-115) ing torque must be used, unless some special pro vision is made. According to the present invention an unloading chamber 65 is provided for facilitating the starting of the compressor. This unloading chamber has its upper end connected by a passage 66 to the inlet of the compressor. The lower end of the unloading chamber is connected to the conduit 2'7. The lower end of the unloading chamber is provided with a threaded plug 67 of magnetic material, preferably soft iron, which is sealed by a suitable gasket 68. This threaded plug 67 has an aperture 69 therein within which'thecompressor end of the suction conduit 2'7 is held. A valve seat '70 is provided upon the top of a threaded plug 6'7 and this seat surrounds the flared upper end of the aperture 69. A thin flexible valve disc '71, preferably of spring steel, which is permanently magnetized rests upon the valve seat '70 when no refrigerant gas is flowing from the conduit 2'7 into the unloading chamber 65. A cage '72 of non-magnetic material, provided with an aperture 73in its upper portion and apertures '74 surround the side portions, is employed for guiding and controlling the vertical movement of the valve disc '71 so as to causeit to fall upon the valve seat '70 when the flow of refrigerant gas from the conduit 2'7 stops. This valve cage '72 secured to the threaded plug 6'7 by having its lower portion forced into a groove which surrounds the upper portion of the threaded plug 67. Instead ofthe valve disc '71 alone being'permanently magnetized, both the valve disc '71 and the threaded plug 6'7 may be permanently magnetized.

When the compressor stops, for example because the low temperature of the evaporator} to which the compressor is connected, has been reached, the check valve '71 quickly closes because of the magnetic attraction between the threaded plug 6'7 and this permanently magnetized valve disc 71. By using thin spring steel, the .valve disc '71 can conform itself to the surface of the valve seat '70 which is preferably ground and polished so that it is preferably smooth and plane to facilitate the seating of the valve disc '71. This quick and positive seating of the valve disc '71 prevents any leaks from the unloading chamber to the suction conduit 2'7. 'At the time the compressor stops there is a comparatively high pressure withinmotor chamber and the chamber beneath the cover 46 of the motor compressor unit. This pressure is approximately equal to the condenser pressure. The compressed refrigerant gas within the above-mentioned chambers forces its way through the oil films which seal the compressor and leaks back through the inlet 58 and the passage 66 into the unloading chamber 65. This leaking back into the unloading chamber 65 continues until the unloading chamber is filled with compressed gas. By filling the unloading chamber 65 with compressed gas, the compressor has refrigerant gas under high pressure on both its discharge side and its inlet side. In this way the compressor is unloaded and can be started by the electric motor with much less starting torque. As the compressor begins to operate, the compressed gas is gradually withdrawn from the unloading chamber 65. When the pressure within the unloading chamber 67 becomes less than the pressure within the suction conduit 27, the valve disc 71 is lifted from its seat 70 by the differential in pressure and the refrigerant gas flows through the unloading chamber to the inlet of the compressor. By employing a magnetized valve at the entrance of the unloading chamber 65, the highly objectionable leakage from the un* loading chamber 65 into the suction conduit 27 is prevented.

By using a thin metal disc for a valve member the weight of the valve is reduced so that it will float upon the incoming gas. Because of the magnetic attraction of the valve disc to its seat.

the valve disc does not leave its seat until there is a sufficient pressure diiferentiaLto overcome the magnetic attraction. Consequently, as soon as the magnetic attraction is overcome by'a sufficient pressure differential, the valve disc rises to the top of the cage wherein it is confined and thus-allows a full opening of the valve without any throttling of the incoming gas or noisy fluttering of the valve disc. The valve disc acts in this way for the reason that as soon as the valve disc lifts from its seat, the magnetic attraction is minimized and then the light weight of the valve disc enables the rush of incoming gas, caused by the pressure differential, to carry the disc quickly to the top of the cage.

For the purpose of illustration,-the compressor unit is now more fully described, and its connection with a refrigerating. system disclosed. The sealed motor-compressor unit is generally designated as 20, where the refrigerant is compressed and forwarded through a conduit '21 to a condensing means comprising a condenser coil 22 forcondensing the refrigerant and a receiver 23 for receiving the condensed refrigerant. From the receiver 23 refrigerant iscchducted through a conduit 24 to an expansion valve 25,, preferably of the automatic type which is responsive to pressure within the evaporator. After passing through the expansion valve 25, the refrigerant flows into the evaporator 26, which may be used for any type of cooling purposes, for example to cool the food storage compartment of a household refrigerator. From the evaporator 26 the evaporated refrigerant is returned to the motor,- compressor unit 20 through the conduit 27.

Within 'the motor-compressor unit 20 is an electric motor generally designated as 28 and a gyratory ring type of compressor generally designated by reference character 29, which compressor is driven by the electric motor 28. The thermostatic control means, generally designated by reference character 30, comprises a switch 31 operated by a bellows member 32 which is connected by a conduit 33 toa thermostatic bulb 34 which is adjacent a portion of the evaporator 26.

with electric current through electric wires 35,

and 36 to provide intermittent operating and idle periods of the motor-compressor unit according to the temperature adjacent the evaporator 26. In this way, the temperature of the evaporator 26 is controlled.

The motor-compressor unit 20 comprises a main casting 40 which supports the stator 41 of the electric motor 28 and the gy ator 42. The bottom plate 43 is fastened to the lower portion of the main casting 40 by the ring 44 and sealed 'thereto by a lead gasket 45. A top cover 46 is secured to the upper portion of the main casting 40 by the cap screws 47 and sealed by the lead gasket 48. A bearing 49 is provided in the bottom plate 43 for supporting the lower end of the driving shaft 50. The upperend of the driving shaft 50 is supported by a bearing 51 which is mounted in a heavy web of metal 52 which extends across the top portion of the main casting 40. The rotor 53 of the electric motor 28 is mounted upon the driving shaft 50 between the bearings 49 and 51 which support the ends of the driving shaft 50. An eccentric 54 is machined upon the upper end of the driving shaft 50 and is surrounded by a ball bearing 55 which fits within the gyrator 42. The unbalanced masses of the eccentric and the gyrator 42 are substantially balanced by the counterbalances '63 and 64. The gyrator 42 has a split ring 56 depending from its lower surface which extends vwithin an annular groove 57 of equal depth in the heavy web 52. A dividing member (not shown) fits within the split portion of the ring 56. On one side of this dividing member is the inlet 58 for the. compressor while on the other side of the divider member are the outlets 59 of the compressor which discharge into the chamber beneath the top cover 46. This cham ber beneath the top cover 46 is in communicapressor, a condensing means connected to the compressor, evaporating means connected to the condensing means, an unloading chamber connected to said compressor, a conduit connecting said evaporating means and said unloading chamber, a check valve. for controlling the flow of fluid between said last mentioned conduit and said unloading chamber, said check valve having a valve seat of magnetic material and a valve adapted to engage said valve seat to cut off the 'flow of fluid, said valve being permanently magnetized to cause the valve to tightly engage the seat when the flow of fluid stops.

2. In a refrigerating system, an intermittent-- ly operating compressor, a condensing means connected to the compressor, evaporating means connected to the condensing means, means connecting said evaporating means and said compressor, and magnetic means for closing said means connecting said evaporating means and said compressor when the flow of fluid stops.

3. A refrigerating system including a compressor, a condensing means connected to the compressor, evaporating means connected to the condensing means, means connecting said evaporating means and said'compressor, and a check valve for controlling the flow of fluid through the means connecting the evaporating means and the compressor, said check valve including magnetic means for quickly and tightly cutting off the fiow of fluid in one direction when the flow of fluid stops, said magnetic means including a valve seat and a valve member, one of said members being of a magnetic material and'the other being permanently magnetized.

4. A refrigerating system including a compressor, a condensing means connected to the compressor, evaporating means connected to the condensing means, means connecting said evaporating means and said compressor, and a check valve for controlling the flow of fluid through the means connecting the evaporating means and the compressor, said check valve including a valve seat member, a valve member adapted to engage said seat member to cut off the flow of fluid, both of said members being permanently magnetized whereby said valve member will be attracted by the magnetic effect to cause the valve member to tightly engage the seat member when the flow of fluid stops.

5. A refrigerating system including a compressor, a condensing means connected to the compressor, evaporating means connected to the condensing means, means connecting said evaporating means and said compressor, and a check valve for controlling the flow of fluid through the means connecting the evaporating means and the compressor, said check valve including a soft iron valve seat, a flexible valve adapted to engage said seat to cut oil the flow of fluid, said flexible valve being permanently magnetized to cause the valve to tightly engage the seat when the flow of fluid stops.

6. A refrigerating system including a compressor, a condensing means connected to the compressor, evaporating means connected to the condensing means, means connecting said evaporating means and said compressor, and a check valve for controlling the flow of fluid through the means connecting the evaporating means and the compressor, said check valve including magnetic means for insuring a quick opening of the check valve unaccompanied by throttling and fluttering of the valve, said magnetic means including a valve seat member and a light weight valve member having a relatively large area, one of the members being of a magnetic material and the other being permanently magnetized.

7. A refrigerating system including a compressor, a condensing means connected to the compressor, evaporating means connected to the condensing means, means connecting said evaporating means and said compressor, and a check valve for controlling the flow of fluid through the means connecting the evaporating means and the compressor, said check valve including magnetic means for insuring a quick opening of the check valve unaccompanied by throttling and fluttering of the valve, said magnetic means including a valve seat member and a light Weight valve member having a relatively large area, one of the members being of a magnetic material and the other being permanently magnetized, a cage of non-magnetic material above said valve seat member and enclosing said valve member for guiding the valve member in a vertical direction and for limiting the upward movement of the valve member.

8. A refrigerating system including a compressor, a condensing means connected to the compressor, evaporating means connected to the condensing means, means connecting said evaporating means and said compressor, and magnetic means responsive to the flow of fluid through saidmeans connecting the -evaporating means and the compressor for tightly closing said connecting means when the fluid flows in one direction and opening the connecting means when the fluid flows in an opposite direction.

JAMES R. HORNADAY. 

